docs: def verify_draft_url(url):
      """
      Return ``True`` if the given URL has a valid draft mode HMAC in its
      querystring.
      """
      url = urlparse.urlparse(url)
      # QueryDict requires a bytestring as its first argument
      query = QueryDict(force_bytes(url.query))
      # TODO Support legacy 'edit' param name for now
      preview_hmac = query.get('preview') or query.get('edit')
      if preview_hmac:
          salt, hmac = preview_hmac.split(':')
          return hmac == get_draft_hmac(salt, url.path)
      return False